• Journal of the Computational Structural Engineering Institute of Korea
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• v.17 no.3
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• pp.295-308
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• 2004

In this study, several Soil-Structure-Interaction (SSI) analyses were performed using the developed FE-BE coupling method and the seismic response behavior of the structure's systems was determined. For the verification of the fundamental solution which is used in this analysis method, a dynamic analysis of the homogeneous ground was performed and it was compared to the results of Estorff et al. In order to verify the seismic response analysis, the results are compared with those of another commercial code. Several kindd of SSI analyses were performed and the seismic response associated with the rile foundation, seismic waves and a consideration of the ground nonlinearity were determined. As a result, it was found that the pile foundations didn't greatly helpful during the seismic event.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.4
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• pp.319-327
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• 2017

In this study, characteristics of seismic behaviors of offshore wind turbine systems using concrete-suction-type supporting structures are investigated. Applying hydrodynamic pressure from the surrounding sea water and interaction forces from the underlying soil to the structural system which is composed of RNA, the tower, and the supporting structure, a governing equation of the system is derived and its earthquake responses are obtained. It can be observed from the analysis results that the responses are significantly influenced by soil-structure interaction because dynamic responses for higher natural vibration modes are increased due to the flexibility of soil. Therefore, the soil-structure interaction must be taken into consideration for accurate assessment of dynamic behaviors of offshore wind turbine systems using concrete-suction-type supporting structures.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.33 no.6
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• pp.383-390
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• 2020

Since the dynamic behaviors of liquid storage tanks on flexible soil are significantly influenced by the fluid-structure-soil interaction (FSSI), its effects must be rigorously considered for accurate earthquake analysis and seismic design of the storage system. In this study, dynamic analysis is performed for a rectangular liquid storage tank on flexible soil, and its dynamic characteristics are examined by rigorously considering the effects of FSSI. The hydrodynamic force and the interaction force between the structure and soil are evaluated using the finite-element approach. In the evaluations, mid-point integrated finite elements and viscous dampers are considered for energy radiation into the infinite soil. The effective earthquake force is then obtained from free-field analysis. It is thus demonstrated that the earthquake responses of the rectangular liquid storage tank on flexible soil are significantly influenced by the FSSI.

• Journal of the Korean Geotechnical Society
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• v.17 no.4
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• pp.173-182
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• 2001

보강토공법이란 다양한 보강재를 흙속에 삽입하여 흙이 갖지 못하는 인장력을 보충함으로써 구조물을 안정화시키는 공법이다. 그리고 기존공법에 비해 경제적 구조물로 인식되고 있으며 또한 최근들어 전세계적으로 빈발하는 지진에도 그 저항력이 아주 큰 구조물임이 입증이 되어 현재 토목분야에서 각광을 받고 있는 공법이다. 보강토옹벽의 뒤채움재료로서 현재 우리나라에서 쉽게 구할 수 있는 화강풍화토가 많이 사용되고 있다. 그러나, 설계에 필요로 하는 이에 대한 데이터는 그리 많지 않다. 본 연구에서는 어디서나 쉽게 구할 수 있는 화강풍화토를 채취하여 대형 인발시험을 실시하였다. 인발시 흙과 보강재 사이의 상호거동을 파악하기 위하여 인발변위, 인발력, 삽입보강재의 각 지점에서의 절점변위 등을 측정하였다. 그리고 구속응력의 영향을 검토하기 위해서 이들 응력을 0.2, 0.5, 1.0kg/$\textrm{cm}^2$으로 변화시켜 실험을 행하였다. 그리고, 다짐률이 이들 상호거동에 어떤 영향을 미치는지 알아보기 위해서 다짐률을 65%, 80%m 95% 등으로 시료를 제작하여 서로 비교를 행하였다. 실험결과로부터 화강풍화토의 보강재와의 상호거동특성을 파악하여 제시하였다. 특히 다짐률은 상호거동특성에 큰 영향을 미치는 것으로 드러났으며, 화강토의 경우, 꽤 큰 점착특성이 존재하고 있음을 알 수 있었다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.37 no.2
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• pp.133-141
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• 2024

Considering fluid-structure-soil interactions, a finite-element model for a liquid-storage tank is presented and the nonlinear earthquake response analysis is formulated. The tank structure is modeled considering shell elements with geometric and material nonlinearities. The fluid is represented by acoustic elements and combined with the structure using interface elements. To consider the soil-structure interactions, the near- and far-field regions of soil are modeled with solid elements and perfectly matched discrete layers, respectively. This approach is applied to the seismic fragility analysis of a 200,000 kL liquid-storage tank. The fragility curve is observed to be influenced by the amplification and filtering of rock outcrop motions at the site when the soil-structure interactions are considered.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.6C
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• pp.255-263
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• 2010

This paper investigates the effects of tunnelling-induced ground movements on nearby structures, considering soil-structure interactions of different construction (ground loss) and soil characteristics. The response of four-story block structures, which are subjected to tunnelling-induced ground movements, has been investigated in different construction (ground loss) and soil conditions using numerical analysis. The structures for numerical analysis has been modelled using Discrete Element Method (DEM) to have real cracks when the shear and tensile stress exceed the maximum shear and tensile strength. The response of four-story block structures has been investigated with a ground movement magnitude and compared in terms of construction (ground loss) and soil conditions considering the magnitude of deformations and cracks in structures. In addition, the damage levels, which are possibly induced in structures, has been provided in terms of construction (ground loss) and soil conditions using the state of strain damage estimation criterion (Son and Cording, 2005). The results of this study will provide a background for better understandings for controlling and minimizing building damage on nearby structures due to tunnelling-induced ground movements.

• Journal of the Earthquake Engineering Society of Korea
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• v.5 no.2
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• pp.23-31
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• 2001

지반 위에 세워진 구조물의 지진응답해석시 지반-구조물 상호작용 영향은 지반으 선형특성을 고려하여 간주되었는데 최근 연구결과에 의하면 구조물 지진해석에서 연약지반의 비선형 특성이 중요한 요소로서 인식되었다. 하지만 지반-구조물계의 복잡한 비선형 특성 때문에 내진설계 기준에서 비선형 지반특성을 고려하기에는 아직도 어려움이 많다. 이 논문에서는 UBC 지반종류 $S_{D}$ 지반 위에 놓인 중규모의 얕은 온통기초와 묻힌 온통기초위에 세워진 건물에 대한 단자유도계 선형 지진해석을 연약지반의 비선형성을 고려하여 최대가속도가 0.17g 과 0.36g 인 Taft E-W 및 El Centro N-S 지진기록을 사용하여 수행하였다. 비선형 지진해석을 결과를 선형해석 결과와 비교하였을 때, 비선형 응답스펙트럼의 최대가속도가 지반의 비선형성 때문에 상당히 줄어드는 것으로 나타나 지반의 비선형성을 고려한 더효율적인 내진설계의 가능성을 보여준다.

• Journal of the Earthquake Engineering Society of Korea
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• v.1 no.1
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• pp.41-49
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• 1997

This paper presents the result of an international cooperative research on the post-correlation analysis of forced vibration tests and the prediction of earthquake responses of a large-scale seismic test structure. The dynamic analysis is carried out using the axisymmetric finite element method incorporating in finite elements for the for field soil region. Through the post-correlation analysis, the properties of the soil layers are revised so that the best correlation in the responses may be obtained compared with the measured force vibration test data. Utilizing the revised soil properties as the initial linear values, the seismic responses are predicted for an earthquake using the equivalent linearlization technique. It has been found that the predicted responses by the equivalent nonlinear procedure are in excellent agreement with the observed responses, while those using the linear properties are fairly off from the measured results.

• Journal of the Korea Concrete Institute
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• v.15 no.2
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• pp.225-233
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• 2003

Even though a lot of advanced researches on analysis, design, and performance evaluation of reinforced concrete (RC) under seismic action have been carried out, there has been only a few study on seismic analysis of underground RC structures surrounding soil medium. Since the underground RC structures interact with surrounding soil medium, a path-dependent soil model which can predict the soil response is necessary for analyzing behavior of the structure inside soil medium. The behavior of interfacial zone between the RC structure and the surrounding medium should be also considered for more accurate seismic analysis of the RC structure. In this paper, an averaged constitutive model of concrete and reinforcing bars for RC structure and path-dependent Ohsaki's model for soil are applied, and an elasto-plastic interface model having thickness is proposed for seismic analysis of underground RC structures. A finite element analysis technique is developed by applying aforementioned constitutive equations and is verified by predicting both static and dynamic behaviors of RC structures. Then, failure mechanisms of underground RC structure under seismic action are numerically derived through seismic analysis of underground RC station structure under different seismic forces. Finally, the changes of failure mode and the damage level of the structures are also analytically derived for different design cases of underground RC structures.

• Journal of the Korean Geotechnical Society
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• v.33 no.4
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• pp.47-56
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• 2017

Aseismic designs of pile-supported wharves are commonly performed utilizing simplified dynamic analyses, such as multi-mode spectral analyses. Simplified analyses can be useful for evaluating the limit state of structures. However, several pile-supported wharves, that have been damaged during past earthquakes, have shown that soil deformation and soil-pile dynamic interaction significantly affect the entire behavior of structures. Such behavior can be captured by performing nonlinear effective stress analyses, which can properly consider the dynamic interactions among the soil-pile-structure. The present study attempts to investigate the earthquake performance of a pile-supported wharf utilizing a three-dimensional numerical method. The damaged pile-supported wharf at the Kobe Port during the Hyogo-ken Nambu earthquake (1995) is selected to verify the applicability of the numerical modeling. Analysis results showed a suitable agreement with the observations on the damaged wharf, and the significant effect of excess pore pressure development and pile-soil dynamic interaction on the seismic performance of the wharf.